import{
    ADD_NUMBER,
    SUB_NUMBER
} from './constants'


function reducer(state ={counter:0},action){
    switch(action.type){
        case ADD_NUMBER:
            return {...state,counter:state.counter+action.num}
         case SUB_NUMBER:
            return {...state,counter:state.counter-action.num}
        default:
            return state
    } 
}

export default reducer